The invention relates to a device for introduction into a human or animal body, especially into an artery for use as a pressure-sensing device.
In the arteries of human and animal bodies, one of the major problems is the loss of strength of the wall of the arteries, which can result in aneurysm formation. An aneurysm may endanger the health of human or animals because of the risk of internal bleeding which often results in death of the patient. Therefore, aneurysms are usually treated before rupture occurs by vascular prostheses, which replace the aneurysmal artery, thus excluding the aneurysm from the circulation.
A new development is the treatment by a so-called endoprosthesis.
Such endoprostheses are well known to the person skilled in the art and can, for example, be positioned within an artery by means of a number of stents. Although the procedure can be safely performed now, endoleakage is still a major problem immediately following the operation even up to many months following surgery. Endoleakage is the incomplete sealing of the arterial wall by the endoprosthesis. Endoleakage can result in a pressure build-up within the aneurysmal sac, enclosed between the wall of the artery and the endoprostheses. Monitoring endoleakage is universally performed by visualization of the endoleakage by means of, for example, a CT-scan, magnetic resonance, duplex ultrasound, and the like. Unfortunately, failure to visualize an endoleak does not exclude the presence of such an endoleak. Also, without a visible endoleak, the aneurysmal sac can still be under pressure with the danger of ultimate rupture and said internal bleeding. Failure to visualize endoleakage can, for example, result from failure to introduce sufficient contrast fluid into the aneurysmal sac that has been filled with a thrombus. This will mean that either no, or a relatively small amount of, blood will leak into the aneurysmal sac, resulting in pressure (without flow) to the arterial wall that may result in rupture. Of course, measuring pressure would be an ideal test to evaluate the absence of an endoleak. However, because of the invasive character of pressure measurement, direct pressure measurements can only be obtained during surgery.
The present invention includes a device for measurement of the pressure within a human or animal body, more specifically in an artery, especially in an aneurysmal sac in an artery between the wall of the artery and the wall of an endoprosthesis. To that effect, a device according to the present invention is characterized by the features of the ensuing claims.
In this application, arteries have to be understood broadly, including, at least, arteries, veins and other blood vessels.
A device according to the present invention can be introduced into a human or animal artery, especially into an aneurysmal sac. The pressure sensor can provide pressure-related data that can be transmitted to a receiving means outside the human or animal body by means of the transponder. Wireless transmission of the data has the advantage of eliminating the need for wires extending from the pressure sensor to the skin of an animal or human. Whenever it is indicated, the pressure data can be obtained from the pressure sensor. These data can be used for the evaluation of pressure that may still be (or has developed again) within the aneurysmal sac. Thus, it is useful for assessment of the state of the artery and the risks of possible rupture of the aneurysm. The device is preferably energized by means of an electrical and/or magnetic field, energizing the device through the transponder. This means that it will not be necessary to provide the device with a battery, enhancing the safety of the human or animal and prolonging the time of use of the device.
In a preferred embodiment a device according to the present invention is characterized by the features of claim 2.
Introduction of the device into an artery through a catheter has the advantage that only a very small operation is necessary for introduction of the device. A catheter can for example be introduced into the artery by using a hollow needle which can be introduced into an artery in for example a leg. Subsequently, through this catheter the device can be introduced and directed to the proper position. The device can be pushed through the same catheter into position as the endoprosthesis, which is used for treatment of the aneurysms if necessary. This will render major operation or additional unnecessary.
Means for storing data, at least connected to at least the transponder, provides for the possibility for storing data taken from the pressure sensor over a prolonged period. Recording such data makes it very easy to obtain information about the occurrence of pressure differences and changes within the artery during that period of time without the necessity of numerous and repetitious measurements by means of a magnetic or electric field and transmitting and receiving means.
Means for positioning the device in a stable position within the artery, especially within an aneurysmal sac, makes easy, stable and secure positioning of the device possible. Such positioning has the advantage that the device will not change its position, at least not significantly, thus enabling even better recording of the pressure data. Comparison of the data will, therefore, be improved.
The invention further relates to device according to the present invention, an endoprosthesis, and, more specifically, an endovascular prosthesis for use in the abdomen.
Prevention of rupture of aneurysmal sacs is especially vital within the abdomen of human and animal bodies. Internal bleeding, especially within the abdomen, can very easily and quickly lead to the death of a human or animal. Thus, adequate recording of the pressure in such aneurysms can be lifesaving.
Means for exciting the transponder when positioned in an artery and for reading the data transmitted from the device to the outside of a human or animal body enable easy and noninvasive measurement of the pressure within the body, especially in an aneurysmal sac in an artery. Such measurements will provide proper and accurate data about the state of the artery, which can be vital to the life of the human or animal.
The present invention further relates to the use of a miniaturized pressure sensor and transponder attached thereto, for introduction into a human or animal artery.
The invention further relates to a method for measuring pressure in an artery of a human or animal body, especially in an aneurysmal sac therein.
Use of a method according to the present invention enables easy and accurate measurement of the pressure within an artery without the necessity of massive operation or repetitive scanning of the relevant parts of the body comprising contrast fluids or the like. A method according to the present invention is thus both patient-friendly and cost-effective for the animal or human.
The pressure sensor and transponder, as well as the endoprothesis, can be brought into position by using a catheter introduced through a hollow needle or the like. Such an operation is nontraumatic and can be performed quickly, easily and accurately.
Furthermore, the present invention relates to the use of a catheter for introduction of a sensor and a transponder into a human or animal body.